Racial differences in screening for prostate cancer in the elderly

BACKGROUND

Black men are more likely than white men to be diagnosed as having advanced prostate cancer, and their prostate cancer mortality rates are more than twice as high. Low screening rates among black men may contribute to these disparities, but there are few data on racial differences in prostate cancer screening.

OBJECTIVES

To present a case-control study of racial differences in the use of prostate-specific antigen (PSA) as a screening test among Medicare beneficiaries in New Jersey and to assess the degree to which race is associated with prostate cancer screening.

METHODS

The study used a statewide database of claims data from Medicare Parts A and B, Medicaid, and the state's Pharmaceutical Assistance for the Aged and Disabled program. Prevalent cases of prostate cancer were excluded using the state's cancer registry. Of 139 672 men who underwent PSA screening, 34 984 were randomly selected along with an identical number of controls matched by month and year of birth. After men with International Classification of Diseases, Ninth Revision, Clinical Modification,or Current Procedural Terminology codes indicative of prostate cancer were excluded, 33 463 case patients and 33 782 control subjects remained.

RESULTS

The use of PSA screening was strongly and inversely associated with black race (odds ratio [OR] = 0.50; P<.001), poverty (OR = 0.33; P<.001), and near poverty (OR = 0.69; P<.001). Multivariate logistic regression analysis after age, socioeconomic status, comorbidity, and use of health care services were controlled for revealed that black race remained a strong predictor of not undergoing PSA screening (OR = 0.65; 95% confidence interval, 0.60-0.70).

CONCLUSIONS

Elderly blacks are substantially less likely to undergo PSA screening than elderly whites. Differences in socioeconomic status and comorbid conditions explain only a small part of the racial differences in screening rates.

Relationship between COX-2 specific inhibitors and hypertension

There is controversy whether cyclooxygenase-2 (COX-2) specific inhibitors are associated with elevations in blood pressure requiring treatment in typical clinical practice. We examined the risk of new onset hypertension in a retrospective case-control study involving 17 844 subjects aged > or =65 years from 2 US states. Multivariable logistic models were examined to assess the relative risk of new onset hypertension requiring treatment in patients who used celecoxib or rofecoxib compared with patients taking either the other COX-2 specific inhibitor, a nonspecific NSAID, or no NSAID. During the 1999 to 2000 study period, 3915 patients were diagnosed and began treatment for hypertension; 4 controls were selected for every case. In no model was celecoxib significantly associated with the development of hypertension. Rofecoxib users were at a significantly increased relative risk of new onset hypertension compared with patients taking celecoxib (odds ratio [OR] 1.6; 95% confidence interval [CI], 1.2 to 2.1), taking a nonspecific NSAID (OR 1.4; 95% CI, 1.1 to 1.9), or taking no NSAID (OR 1.6; 95% CI, 1.3 to 2.0). There were no clear dosage or duration effects. In patients with a history of chronic renal disease, liver disease, or congestive heart failure, the relative risk of new onset hypertension was twice as high in those taking rofecoxib compared with celecoxib (OR 2.1; 95% CI, 1.0 to 4.3). In this retrospective case-control study of patients aged > or =65 years, rofecoxib use was associated with an increased relative risk of new onset hypertension; this was not seen in patients taking celecoxib.

Relationship Between Selective Cyclooxygenase-2 Inhibitors and Acute Myocardial Infarction in Older Adults

Background— Although cyclooxygenase-2 inhibitors (coxibs) were developed to cause less gastrointestinal hemorrhage than nonselective nonsteroidal antiinflammatory drugs (NSAIDs), there has been concern about their cardiovascular safety. We studied the relative risk of acute myocardial infarction (AMI) among users of celecoxib, rofecoxib, and NSAIDs in Medicare beneficiaries with a comprehensive drug benefit.

Methods and Results— We conducted a matched case-control study of 54 475 patients 65 years of age or older who received their medications through 2 state-sponsored pharmaceutical benefits programs in the United States. All healthcare use encounters were examined to identify hospitalizations for AMI. Each of the 10 895 cases of AMI was matched to 4 controls on the basis of age, gender, and the month of index date. We constructed matched logistic regression models including indicators for patient demographics, healthcare use, medication use, and cardiovascular risk factors to assess the relative risk of AMI in patients who used rofecoxib compared with persons taking no NSAID, taking celecoxib, or taking NSAIDs. Current use of rofecoxib was associated with an elevated relative risk of AMI compared with celecoxib (odds ratio [OR], 1.24; 95% CI, 1.05 to 1.46; P =0.011) and with no NSAID (OR, 1.14; 95% CI, 1.00 to 1.31; P =0.054). The adjusted relative risk of AMI was also elevated in dose-specific comparisons: rofecoxib ≤25 mg versus celecoxib ≤200 mg (OR, 1.21; 95% CI, 1.01 to 1.44; P =0.036) and rofecoxib >25 mg versus celecoxib >200 mg (OR, 1.70; 95% CI, 1.07 to 2.71; P =0.026). The adjusted relative risks of AMI associated with rofecoxib use of 1 to 30 days (OR, 1.40; 95% CI, 1.12 to 1.75; P =0.005) and 31 to 90 days (OR, 1.38; 95% CI, 1.11 to 1.72; P =0.003) were higher than >90 days (OR, 0.96; 95% CI, 0.72 to 1.25; P =0.8) compared with celecoxib use of similar duration. Celecoxib was not associated with an increased relative risk of AMI in these comparisons.

Conclusions— In this study, current rofecoxib use was associated with an elevated relative risk of AMI compared with celecoxib use and no NSAID use. Dosages of rofecoxib >25 mg were associated with a higher risk than dosages ≤25 mg. The risk was elevated in the first 90 days of use but not thereafter.

Determinants of selective cyclooxygenase-2 inhibitor prescribing: are patient or physician characteristics more important?

BACKGROUND

Little is known about which factors influence the widespread use of selective cyclooxygenase (COX)-2 inhibitors. We examined the relative effects of patient risk factors for gastrointestinal toxicity, other patient characteristics, and physician prescribing preferences on the decision to prescribe a selective COX-2 inhibitor.

METHODS

We retrospectively studied a cohort of 28,190 Medicare beneficiaries who were continuously enrolled in a large, state-run pharmacy benefits program that reimbursed for selective COX-2 inhibitors and nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) without restrictions. Half of the study sample filled a prescription for a selective COX-2 inhibitor and the other half for a nonselective NSAID. Multivariable logistic regression models were developed to predict COX-2 inhibitor use.

RESULTS

Seventeen percent of patients using a COX-2 inhibitor had no identifiable risk factor for NSAID-associated gastrointestinal toxicity, compared with 23% of those using a nonselective NSAID. Established risk factors (age > or =75 years, history of gastrointestinal hemorrhage or peptic ulcer disease, or concomitant warfarin or oral glucocorticoid use) were all significant predictors of COX-2 inhibitor use, but a multivariable model including only these risk factors discriminated poorly between the two patient groups (C statistic = 0.55). Adding other patient clinical and demographic characteristics to the model somewhat improved this association (C statistic = 0.66); however, when physician prescribing preference was included, the model had excellent ability to discriminate between the two treatment groups (C statistic = 0.83).

CONCLUSION

Established risk factors for NSAID-associated gastrointestinal toxicity were poor predictors of who was prescribed a selective COX-2 inhibitor; in contrast, physician prescribing preference was an important determinant.

Hetastarch and Bleeding Complications After Coronary Artery Surgery

STUDY OBJECTIVES

Controversy persists concerning the potential association between intraoperative use of hetastarch (ie, hydroxyethyl starch [HES]) and postoperative bleeding in patients undergoing surgery. To determine whether intraoperative HES use is associated with an increased risk of postoperative bleeding following coronary artery bypass graft (CABG) surgery.

DESIGN

Case-control study.

SETTING

A large academic medical center in the northeastern United States.

PARTICIPANTS

A consecutive sample of 238 patients undergoing CABG surgery.

MAIN OUTCOME MEASURES

Cases consisted of patients who had received either > or = 3 U packed RBCs, > or = 3 U platelets, > or= 3 U fresh frozen plasma, or any cryoprecipitate within 72 h after undergoing a CABG procedure, or who had undergone surgical revision for bleeding. All other CABG surgery patients served as control subjects.

RESULTS

In multivariate models that controlled for a wide variety of demographic and clinical characteristics, we found that, compared to patients who did not receive any HES during surgery, those who received 1 U intraoperative HES had more than twice the risk of a bleeding outcome (odds ratio [OR], 2.32; 95% confidence interval [CI], 1.10 to 4.91), and those who received 2 or 3 U HES had more than four times the risk of postoperative bleeding (OR, 4.57; 95% CI, 1.74 to 12.00).

CONCLUSIONS

HES use in patients undergoing CABG surgery may be associated with a significant risk of postoperative bleeding. A double-blinded, randomized, controlled trial will be necessary to confirm this finding.

Hydroxyethyl starch and change in renal function in patients undergoing coronary artery bypass graft surgery

BACKGROUND

Several case reports and clinical lore have suggested that exposure to the colloid hydroxyethyl starch may impair renal function, but few studies have systematically addressed this issue, and several have produced conflicting results. We sought to study the question in a formal analysis of postoperative change in renal function in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

We identified 238 consecutive patients who underwent CABG surgery at a large academic medical center. Glomerular filtration rate (GFR) was estimated using the Cockroft-Gault formula at baseline as well as on postoperative days 3 and 5. Linear regression analysis was used to study the relation between changes in GFR and intraoperative hydroxyethyl starch administration. Multivariate models controlled for potential demographic, clinical, and surgery-related confounders.

RESULTS

Hydroxyethyl starch use was independently associated with a reduction in GFR on both postoperative days 3 and 5, with GFR declining by 7.2 mL/min/1.73 m2 on day 3 per unit of hydroxyethyl starch administered (95% CI, 1.7 to 12.7; P = 0.012), and by 6.6 mL/min/1.73 m2 on day 5 (95% CI, 1.2 to 11.9; P = 0.018).

CONCLUSION

Intraoperative use of hydroxyethyl starch may be associated with modest impairment in renal function in patients undergoing CABG surgery. Randomized clinical trials will be necessary to confirm these findings and to further investigate their clinical implications.

The nephrologist's role in the management of calcium-phosphorus metabolism in patients with chronic kidney disease

BACKGROUND

In patients with chronic kidney disease (CKD), timely referral to a nephrologist has been shown to improve outcomes, but the specific care measures mediating these superior outcomes have not been sufficiently described.

METHODS

In a cohort of 3014 patients with CKD, we evaluated whether they had any indicators of calcium-phosphorus metabolism management prior to renal replacement therapy (RRT). These included measurement of parathyroid hormone (PTH) or vitamin D metabolites, or receipt of calcitriol or calcium-containing phosphate binders (CCPB) prior to RRT. Control patients without such care were selected by risk-set matching. We used multivariate conditional logistic regression analysis to test whether use of these interventions was associated with prior nephrologist consultation. We then used Cox proportional hazards models to assess whether implementation of such care was associated with differences in 1-year mortality once RRT was instituted.

RESULTS

Only 3.4% of CKD patients had their PTH assessed prior to RRT, and 0.3% had vitamin D status measured. Use of calcitriol (12.2%) and CCPBs (16%) was slightly more prevalent. Seeing a nephrologist was highly associated with use of the tests and drugs studied (odds ratio, 1.28 to 6.46; all P values <0.001), but care by generalists or other specialists was not. Management of calcium-phosphorus metabolism was independently associated with a 35% decreased likelihood of death (hazards ratio=0.65; 95%CI, 0.51 to 0.84) in the first year of RRT.

CONCLUSION

Improvements in management of calcium-phosphorus metabolism in patients with CKD are attributable to nephrologist care and appear to mediate the survival benefit seen in patients who see a nephrologist relatively early in the course of their CKD.

The hidden cost of nonselective nonsteroidal antiinflammatory drugs in older patients

OBJECTIVE

Nonselective nonsteroidal antiinflammatory drugs (NSAID) are well known to cause an increased risk of gastrointestinal (GI) hemorrhage, congestive heart failure, and hypertension, but the cost of such adverse effects has not been rigorously defined. We calculated the excess risk and costs associated with the major adverse effects of prescription nonselective NSAID.

METHODS

This study involved a retrospectively collected random cohort of 41,826 continuously enrolled patients over 65 years old in the New Jersey Pharmaceutical Assistance to the Aged and Disabled or Medicaid programs. We calculated the adjusted rates and costs of major adverse effects associated with nonselective NSAID, including hospitalization for GI hemorrhage, gastroprotective drug use, ambulatory upper GI procedures, antihypertensive drug use, and hospitalization and medication use to treat congestive heart failure.

RESULTS

Eighteen percent of patients filled > or = 1 new prescription for a nonselective NSAID during the study year. All adverse effects studied were more common in patients filling prescriptions for nonselective NSAID than in those not. Average annual costs for the adverse effects studied were 1,234 (1998 US dollars) in nonselective NSAID users compared with 1,036 (1998 US dollars) for controls. After adjusting for sociodemographic factors, other health care utilization, and relevant comorbid diseases, the average annual cost for the major nonselective NSAID related adverse effects studied was 117 (1998 US dollars) higher for patients filling a nonselective NSAID prescription than for those who did not. Nonselective NSAID users with > or = 4 risk factors for nonselective NSAID related adverse effects had average excess costs of 316 (1998 US dollars) over controls, whereas those with no risk factors had an average excess cost of only 75 (1998 US dollars) .

CONCLUSION

The excess cost of nonselective NSAID related adverse effects is modest in low risk patients, but much higher in patients with specific risk factors. This approach of stratifying patients based on the risk of nonselective NSAID associated adverse effects can help clinicians and policymakers determine which patients might be the most appropriate candidates for treatment options costlier than nonselective NSAID.

A propensity analysis of late versus early nephrologist referral and mortality on dialysis

Previous studies have analyzed the association between late versus early nephrologist referral (LR, ER) and poor clinical outcomes in patients with end-stage renal disease. We sought to determine whether these poor outcomes were causally related to LR, or whether LR was a proxy for poorer access to health care in general. An inception cohort of incident dialysis patients enrolled in the New Jersey Medicare or Medicaid programs was identified. Using a large number of demographic, clinical, and health care utilization covariates, propensity scores (PS) were then calculated to predict whether a given patient had been seen by a nephrologist at 90 d before first dialysis. Cox proportional hazards models were then built to test the association between timing of nephrologist referral and mortality during the first year of dialysis, using PS adjustment and matching to determine whether this association was confounded by other measures of reduced healthcare utilization. Neither adjustment for PS (HR = 1.31; 95% CI, 1.17 to 1.47) nor matching (HR = 1.40; 95% CI, 1.23 to 1.59) materially changed the initial 36% excess mortality in LR compared with ER patients (HR = 1.36; 95% CI, 1.22 to 1.51). Excess mortality among LR was limited to the first 3 mo of dialysis (HR = 1.75; 95% CI, 1.48 to 2.08) but not present thereafter (HR = 1.03; 95% CI, 0.84 to 1.25). Late nephrologist referral is an independent risk factor for early death on dialysis, even after controlling for other indicators of healthcare utilization. Further research is needed to identify patients at particular risk so that interventions to prevent early deaths on dialysis in LR patients can be developed and tested.

Chronic kidney disease as a risk factor for bleeding complications after coronary artery bypass surgery

BACKGROUND

The aim of the study is to define the role of chronic kidney disease (CKD) as a risk factor for postoperative bleeding in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

This is a retrospective cohort study of 238 consecutive patients who underwent isolated CABG surgery. Patients were followed up for the event of a significant bleed, defined as administration of either three or greater units of packed red blood cells, three or greater units of platelets, three or greater units of fresh frozen plasma, or any cryoprecipitate within 72 hours after a CABG procedure or undergoing a surgical revision for bleeding. Glomerular filtration rate (GFR) at baseline was calculated using the Cockroft-Gault formula. A final multiple logistic regression model was selected from a large set of presurgical and intraoperative covariates by using backward elimination (P > 0.20).

RESULTS

After controlling for age, sex, elective versus emergent surgery, intraoperative activated clotting time, serum albumin level, extracorporeal bypass time, and baseline hematocrit, we found that even mild levels of renal impairment were associated with increased risk for postoperative bleeding: patients with a GFR of 40 mL/min or less had six times the odds of postoperative bleeding than patients with a GFR greater than 100 mL/min (odds ratio [OR], 6.51; 95% confidence interval [CI], 1.87 to 22.66); those with a GFR of 41 to 60 mL/min had nearly four times the risk (OR, 3.87; 95% CI, 1.21 to 12.35). Even patients with mild CKD at a GFR of 61 to 80 mL/min were at an elevated risk (OR, 2.11); however, the 95% CI of 0.79 to 5.64 included the null value. Similar results were found when using the cruder Kidney Disease Outcomes Quality Initiative classification of CKD.

CONCLUSION

CKD is associated with risk for postoperative bleeding in patients undergoing CABG surgery, not only at more advanced stages, but probably at relatively mild levels of renal impairment, as well.

Dopamine antagonists and the development of breast cancer

BACKGROUND

Although animal studies have raised the possibility that prolactin-elevating dopamine antagonists used to treat psychotic disorders may initiate and promote breast cancers, epidemiologic studies in humans have been limited and inconsistent.

METHODS

A retrospective cohort study was conducted of 52 819 women exposed and 55 289 not exposed to dopamine antagonists between January 1, 1989, and June 30, 1995. All participants were 20 years or older, initially free of breast cancer, and enrolled in the Medicaid or the Pharmaceutical Assistance to the Aged and Disabled programs of New Jersey. Incident breast cancer cases were identified through the New Jersey Cancer Registry and definitive breast cancer surgeries. Adjusted hazard ratios of breast cancer were calculated from multivariable proportional hazards models.

RESULTS

Use of antipsychotic dopamine antagonists was associated with a 16% increase in the risk of breast cancer (adjusted hazard ratio, 1.16; 95% confidence interval, 1.07-1.26), with a dose-response relationship between larger cumulative dosages and greater risk. The increased risk was also seen in women who used prolactin-elevating antiemetic dopamine antagonists despite having different breast cancer risk profiles than antipsychotic dopamine antagonist users. Dopamine antagonist use was not associated with risk of colon cancer, a control condition not related to elevated prolactin levels. The increased risk of breast cancer among dopamine antagonist users was not explained by increased surveillance or protopathic bias.

CONCLUSIONS

Antipsychotic dopamine antagonist use may confer a small but significant risk of breast cancer. In light of the small hazards and the possibility of residual confounding, these findings should lead to follow-up investigations but not to changes in treatment strategies.

Nephrologist care and mortality in patients with chronic renal insufficiency

BACKGROUND

For patients with chronic renal insufficiency, rates of referral to nephrologists are highly variable, and little is known about the effect of such consultation on clinical outcomes. We sought to determine whether early or frequent access to nephrologist care prior to the initiation of dialysis was associated with a difference in mortality rates in the first year after dialysis began.

METHODS

We identified all patients in the New Jersey Medicaid and Medicare programs who began maintenance dialysis during a 6-year period and who had been diagnosed with renal disease more than 12 months prior to dialysis. Use of nephrologist services was documented during this 1-year period, along with other clinical and sociodemographic variables. The outcome measure of our analysis was mortality in the first year after initiation of dialysis.

RESULTS

From multivariate analyses, we found that patients who did not see a nephrologist until 90 days or less before initiation of dialysis had a 37% higher likelihood of death in the first year of dialysis compared with patients with earlier referral (95% confidence interval, 1.22-1.52; P<.001). Similarly, those who saw a nephrologist on fewer than 5 occasions in the year prior to dialysis had a 15% higher mortality rate in the first year of dialysis compared with those who had had 5 or more nephrologist visits (95% confidence interval, 1.03-1.28; P =.01).

CONCLUSIONS

For patients with long-standing renal disease, earlier consultation with a nephrologist and more frequent specialist encounters is associated with lower mortality in the first year of dialysis. These findings need to be confirmed in younger and less indigent patients as well.

Comparing mortality of elderly patients on hemodialysis versus peritoneal dialysis: a propensity score approach

The objective of this study was to evaluate differences in mortality over the first year of renal replacement therapy (RRT) between elderly patients starting treatment on hemodialysis (HD) versus peritoneal dialysis (PD). For the period of 1991 to mid-1996, this study defined an inception cohort of all patients aged >65 yr with new-onset chronic RRT who were New Jersey Medicare and/or Medicaid beneficiaries in the year before RRT and who had been diagnosed with renal disease more than 1 yr before RRT. Propensity scores were calculated for first treatment assignment from a large number of baseline covariates. Mortality was then compared among patients initially assigned to HD versus PD using multivariate 90-d interval Cox models controlled for propensity scores and center stratification. Peritoneal dialysis starters had a 16% higher rate of death during the first 90 d of RRT compared with HD patients (hazard ratio [HR], 1.16; 95% confidence interval [CI], 0.96 to 1.42)]. Mortality did not differ between day 91 and 180 (HR, 1.03; 95% CI, 0.71 to 1.51). Thereafter, PD starters again died at a higher rate (HR, 1.45; 95% CI, 1.07 to 1.98). These findings were more pronounced among patients with diabetes. Sensitivity analyses using more stringent criteria to ensure that first treatment choice reflected long-term treatment choice confirmed the presence of an association between PD and mortality. In conclusion, compared with HD, peritoneal dialysis appears to be associated with higher mortality among older patients, particularly among those with diabetes, even after controlling for a large number of risk factors for mortality, propensity scores to control for nonrandom treatment assignment, and center stratification.

Preventive health care measures before and after start of renal replacement therapy

OBJECTIVE

To describe utilization of preventive health care measures in patients with chronic kidney disease (CKD), both in the year prior to onset of renal replacement therapy (RRT), and in the first year of RRT.

METHODS

We identified a large cohort of patients with CKD in the New Jersey Medicaid and Medicare programs with fixed enrollment into the cohort at 1 year prior to RRT. We applied commonly used quality assurance instruments (Health Plan Employer Data and Information Set measures) and defined levels and correlates of use of preventive care measures before and after RRT. These included mammography, Pap smear testing, prostate cancer screening, diabetic eye exams, and glycosylated hemoglobin testing (HbA1c). We employed logistic regression models with adjustment for age, race, gender, comorbidity, timing of first nephrologist contact, socioeconomic status, and calendar year of first RRT.

RESULTS

Overall, screening rates were low with the exception of diabetic eye exams. Prostate cancer screening, diabetic eye exams, and HbA1c testing were performed less often after onset of RRT compared to the year before (P < .05). Although screening rates before RRT improved considerably over the period of observation for these measures (P < .05), this was not the case once patients were on RRT.

CONCLUSIONS

Preventive health care interventions remain underutilized among RRT patients. Greater attention to such preventive measures could lead to significant improvements in the health status of such vulnerable patients. Thus, quality improvement of the general health care for patients on RRT should become a priority in renal health policy.

Delayed nephrologist referral and inadequate vascular access in patients with advanced chronic kidney failure

We sought to determine whether late referral to a nephrologist in patients with chronic renal failure influences the adequacy of vascular access for hemodialysis. We analyzed data describing all health care encounters for all Medicare and Medicaid patients with end-stage renal failure in New Jersey between January 1991 and June 1996. Patients were required to have been diagnosed with renal disease at least 1 year prior to onset of hemodialysis. In the resulting cohort of 2,398 incident hemodialysis patients, 35% had their first nephrologist consultation < or =90 days prior to initiation of dialysis. After controlling for demographic characteristics, socio-economic status and underlying renal disease, we found that patients who were referred to a nephrologist >90 days prior to onset of hemodialysis were 38% more likely to have undergone predialysis vascular access surgery than those who were referred to a nephrologist < or =90 days before dialysis [OR: 1.38; 95% CI (1.15; 1.64)]. Similarly, patients referred late were 42% more likely to require central venous access for hemodialysis compared to those seen by a nephrologist early [OR: 1.42; 95% CI (1.17; 1.71)]. Inadequate development of vascular access for renal replacement therapy in patients with late nephrologist referral unnecessarily contributes to the burden of disease experienced by this vulnerable patient population.

Late nephrologist referral and access to renal transplantation

BACKGROUND

Our aim was to explore a possible association between late nephrologist referral before onset of renal replacement therapy (RRT) and the likelihood of receiving a renal transplant.

METHODS

For the period of 1991 to mid-1996 we defined an inception cohort of all patients with new-onset chronic RRT who were New Jersey Medicare and/or Medicaid beneficiaries in the year before RRT and who had been diagnosed with renal disease more than 1 year before RRT. To control for known risk factors and confounders of access to renal transplantation, we conducted a matched case-control study. Using number of days from onset of RRT to transplantation as the index date for cases, we successfully matched 32 transplant recipients (cases) with 197 controls who shared the cases' age (+/-2 years), gender, race (white/black/other), and year of onset of RRT (+/-1 year) but had not received a transplant on index date. Using conditional logistic regression, we evaluated the effects on the likelihood of transplantation of late referral (< or = 90 days vs. >90 days before first RRT) and socioeconomic status (lower socioeconomic status indicated by enrollment in Medicaid or another state program for the poor), further controlling for comorbidity (Charlson score) in the year before index date.

RESULTS

In the full multivariate conditional model, late referral was significantly associated with a much lower rate of renal transplantation (odds ratio [OR]=0.22; 95% confidence interval [CI]: 0.05, 0.97), as were socioeconomic status (OR=0.18; 95% CI: 0.04, 0.82) and comorbidity status (OR=0.69; 95% CI: 0.48, 1.00).

CONCLUSIONS

Delayed referral of renal patients to a nephrologist before RRT is significantly associated with reduced access to renal transplantation, independent of age, gender, race, socioeconomic and comorbidity status. The validity of our result needs to be confirmed in larger populations.

Clozapine use and risk of diabetes mellitus

Recent reports have raised the concern that clozapine increases the risk for diabetes mellitus. Accurate pharmacoepidemiologic data on whether such a hazard exists and its magnitude are needed to enable clinicians and patients to make proper treatment decisions about clozapine. The authors performed a case-control study involving 7,227 cases of newly treated diabetes and 6,780 controls, all with psychiatric disorders. Cases and controls were older than 20 years and enrolled in government-sponsored drug benefit programs in New Jersey. The authors measured the use of clozapine or other antipsychotic medications and additional covariates. They developed logistic regression models adjusted for demographic, clinical, and health care use characteristics to identify whether clozapine users were at increased risk to begin treatment for diabetes. Clozapine use was not significantly associated with developing diabetes (adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.74-1.31). There was no suggestion of relationships between larger dosages or longer durations of clozapine use and increasing risks of diabetes. On the other hand, nonclozapine antipsychotic medication use was associated with a modest but significantly increased risk of developing diabetes (adjusted OR, 1.13; 95% CI, 1.05-1.22). Among individual nonclozapine antipsychotics, significantly elevated risks were observed for two phenothiazine agents: chlorpromazine (adjusted OR, 1.31; 95% CI, 1.09-1.56) and perphenazine (adjusted OR, 1.34; 95% CI, 1.11- 1.62). In contrast to earlier reports, these results provide some reassurance that clozapine does not increase the risk of developing diabetes. Additional data from pharmacoepidemiologic studies and randomized controlled trials are needed to exclude the possibility of residual confounding and ensure the appropriate use of this agent.

Nonsteroidal anti-inflammatory drug use and acute myocardial infarction

BACKGROUND

Although aspirin has been shown to protect patients from acute myocardial infarction (AMI), the effect of nonaspirin nonsteroidal anti-inflammatory drugs (NSAIDs) is not clear.

OBJECTIVE

To determine whether NSAIDs have a similar effect or whether they differ in their effect on the risk of AMI.

METHODS

We performed a case-control study of AMI in a large health care database containing information on all filled prescriptions, hospitalizations, diagnoses, and procedures for all patients covered by the New Jersey Medicaid or Medicare and Pharmaceutical Assistance for the Aged and Disabled programs. We identified 4425 patients hospitalized for AMI between January 1, 1991, and December 31, 1995, and 17 700 control subjects. Multivariate models were constructed to control for potential confounders.

RESULTS

A quarter of the cases and controls had filled a prescription for an NSAID in the 6 months before theirAMI (cases) or a randomly assigned index date (controls); 9% had filled a prescription for an NSAID that overlapped with their date of AMI or index date. Overall, NSAID users had the same risk of AMI as nonusers, whether such use was measured on the index date (adjusted odds ratio, 1.04; 95% confidence interval, 0.92-1.18; P =.55) or at any time in the prior 6 months (adjusted odds ratio, 1.00; 95% confidence interval, 0.92-1.08; P =.92). However, use of naproxen was associated with a significant reduction in the risk of AMI (adjusted odds ratio, 0.84; 95% confidence interval, 0.72-0.98; P =.03).

CONCLUSIONS

Although NSAIDs have anti-inflammatory and antiplatelet effects similar to those of aspirin, we did not find that these drugs confer a protective effect against AMI. However, use of one specific NSAID, naproxen, appeared to be associated with a reduced rate of AMI, an effect recently suggested by a large randomized controlled trial as well.

Urinary antispasmodic use and the risks of ventricular arrhythmia and sudden death in older patients

OBJECTIVES

The introduction of new medications to treat overactive bladder has resulted in a significant increase in the number of individuals with this condition who use medications for symptoms. Formal epidemiological studies of the safety of these medications in typical patient populations are lacking, particularly studies of serious events. We sought to determine whether the use of urinary antispasmodics increases the risk of ventricular arrhythmias or sudden death.

DESIGN

Retrospective cohort study.

SETTING

Retrospective analysis of data of participants in community, hospital or nursing home setting.

PARTICIPANTS

Fourteen thousand six hundred thirty-eight subjects with a diagnosis of urinary incontinence made between January 1, 1991, and June 30, 1995; all were aged 65 and older and enrolled in Medicare and Medicaid or the Pharmacy Assistance for the Aged and Disabled programs of New Jersey.

MEASUREMENTS

Filled prescriptions for oxybutynin (Ditropan), flavoxate (Urispas), hyoscyamine (Cystospas), and hyoscyamine sulfate (Cystospas-M) were used to define days of exposure to these drugs. We also identified all use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors, and their concurrent use, to serve as a positive control exposure. Two outcomes were then defined: a new diagnosis of ventricular arrhythmia combined with initiation of an antiarrhythmic medication and sudden death. Other covariates, including clinical, demographic, medication use, and healthcare utilization variables, were also assessed. Adjusted risk ratios of ventricular arrhythmia and sudden death were derived from multivariable Cox proportional hazards models.

RESULTS

There was no significant association between periods of use of urinary antispasmodics and the development of ventricular arrhythmias (adjusted risk ratio (RR) = 1.23, 95 confidence interval (CI) = 0.87-1.75) or sudden death (adjusted RR = 0.70, 95% CI = 0.28-1.74). A significantly increased risk of ventricular arrhythmia was observed for the positive control regimen, concurrent use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors (adjusted RR = 5.47; 95% CI = 1.34-22.26), but not for use of either drug group alone. Concurrent use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors was also associated with a significant increase in the risk of sudden death (adjusted RR = 21.50, 95% CI = 5.23-88.37). Other variables significantly associated with ventricular arrhythmia included ischemic heart disease and congestive heart failure, whereas nursing home use before the index date was associated with a decreased likelihood of receiving a diagnosis of and treatment for ventricular arrhythmia. Other variables significantly associated with sudden death included male gender, black race, and congestive heart failure.

CONCLUSIONS

Antimuscarinic urinary antispasmodics available before 1996 were not associated with an increased risk of ventricular arrhythmias and sudden death. Additional study will be required to confirm these results, exclude the possibility of unmeasured confounders contributing to any lack of an observed relationship, and extend these findings to newer agents such as tolterodine.

Determinants of delayed nephrologist referral in patients with chronic kidney disease

Late referral to nephrologists of patients with chronic kidney disease (CKD) is a major public health problem because it is prevalent and associated with increased morbidity, mortality, and greater healthcare costs. To identify factors associated with delayed nephrologist referral (first nephrologist visit < 90 days before the onset of renal replacement therapy), we identified a cohort of patients with preexisting CKD that progressed to end-stage renal failure. We developed a logistic regression model to measure the association of specific demographic and clinical covariates with delayed nephrologist referral. Delayed referral was highly associated with older age (P < 0.001), race other than white or black (P = 0.002), and the absence of certain comorbidities: hypertension (P < 0.001), coronary artery disease (P < 0.001), malignancy (P = 0.005), and diabetes (P = 0.02). Associations of late referral with male sex (P = 0.07) and lower socioeconomic status (P = 0.09) were of borderline significance. Patients who were predominantly cared for by a general internist were more likely to be referred late to a nephrologist compared with those cared for by a family or primary care practitioner (P = 0.002) or another subspecialist (P = 0.019). These findings suggest that several factors increase the risk that patients with CKD will have the first nephrologist consultation excessively late in the course of their disease. Although timely access to nephrologist services is important for all patients with advanced CKD, this is of particular concern in older patients, those in certain minority populations, and those in whom the absence of comorbidity may provide a false sense of true risk status.

Paradoxical relations of drug treatment with mortality in older persons

Medication use patterns provide popular surrogate measures of disease, yet selective under-use of drugs by elderly patients with potentially unmeasured comorbidity may lead to artifactual "protective" associations between use of specific drugs and mortality. We examined the relation between use of 20 common classes of drugs and mortality among the 129,111 residents of New Jersey 65-99 years of age who had at least one hospitalization during the years 1991-1994 and filled prescriptions through either Medicaid or that state's Pharmacy Assistance for the Aged and Disabled program. Each study drug class was used by more than 5,000 subjects during the 120 days before hospitalization; 41,930 subjects died in the hospital or during the year after discharge. Users of drugs from each of seven therapeutic classes had reduced age- and sex-adjusted rates of death relative to non-users: lipid-lowering agents, nonsteroidal anti-inflammatory agents, beta blockers, thiazides, glaucoma drugs, calcium channel blockers, and anti-anxiety drugs. Adjustment for comorbidity and polypharmacy had little effect on these results. We found similar results in a separate nonhospitalized cohort of 132,071 elderly persons. Much of this observed association appears to be nonetiologic. These findings raise concerns about using observational studies in high-risk populations to infer associations between drug use and outcomes.

Late referral and modality choice in end-stage renal disease

BACKGROUND

We sought to determine whether late versus early referral to a nephrologist in patients with chronic kidney disease influences the initial choice of hemodialysis (HD) versus peritoneal dialysis (PD) or the likelihood of switching treatment modalities in the first six months of therapy.

METHODS

Using New Jersey Medicare/Medicaid claims, all patients who started RRT between January 1991 and June 1996 and were diagnosed with renal disease more than one year prior to RRT were identified. In the resulting cohort of 3014 patients, 35% had their first nephrologist consultation < or =90 days prior to initiation of dialysis.

RESULTS

After controlling for demographic characteristics, socioeconomic status and underlying renal disease, age, black race [Odds ratio (OR) = 0.56], race other than black or white (OR = 0.56), and socioeconomic status (OR = 0.68) influenced the choice of initial treatment modality, but timing of the referral did not. However, patients starting on PD who were referred late were 50% more likely to switch to HD than were patients who saw a nephrologist earlier [Hazard's ratio (HR) = 1.47]. In patients originally on HD, diabetic nephropathy (HR = 1.49) and black race (HR = 0.69) influenced the likelihood of switching to PD, but the timing of referral did not.

CONCLUSIONS

These results refute earlier findings that late referral may limit access to PD. We found that modality choice depends on factors such as age, race, or socioeconomic status, rather than on than timing of nephrologist referral. Late referral does not influence the likelihood to switch modality in patients starting on HD, but does so in patients starting on PD.